The present invention relates to electronic equipment for electrophysiology studies and in particular to an interface for electrophysiology devices that reduces interference and conflict among the electrophysiology devices.
Electrophysiology studies provide complex measurements of the electrical activity and conduction pathways of the heart that may be used, for example, to analyze and treat heart arrhythmias. An example study may use multiple surface ECG electrodes applied to the patient's skin together with intra-cardiac electrodes inserted into the patient's heart and monitoring electrical activity directly on the muscle wall of the heart. Electrical stimulation may be applied to the heart muscle through an intra-cardiac pacing electrodes to promote heart action that may be monitored. An intra-cardiac ablation electrode may be used to burn tissue of the heart to alter heart conduction pathways in a manner that may reduce or stop arrhythmia. A mapping device may use signals from a catheter in the heart, for example, providing an insertion path for intra-cardiac electrodes or one of the intra-cardiac electrodes to locate the position of the intra-cardiac electrodes.
In an electrophysiology study, multiple devices must have access to electrical signals from the body. Those devices typically include an ECG monitor for monitoring patient heartbeat, a stimulator device for providing pacing signals to the heart through one or more intra-cardiac electrodes, an intra-cardiac signal-recording device recording signals from the intra-cardiac electrodes, a mapping device determining a location of the intra-cardiac electrodes, and an ablation circuit providing ablative power through one or more of the intra-cardiac electrodes. Other devices such as x-ray equipment may also require access to these electrical signals, for example, for the purpose of gating image data to particular physiological activity such as respiration or cardiac cycle.
As a practical matter, these multiple devices must share limited electrode resources either in the form of discrete electrodes or practical locations for electrodes. Electrically sharing individual electrodes can generate cross-coupled noise between devices, problems with ground stabilization, and direct interference from conflicting uses, for example, between ablation or pacing and the measurement of sensitive physiological signals. Competing and different filtration requirements can make shared electrodes impractical in many cases and substantially increase the amount of time setting up and troubleshooting circuit paths in the operating room.